Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.61 (caspase-8)
 6,833 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been reported that at the end stage, apoptosis is involved in the progression of heart failure. It is suggested that cardiac energy metabolism is impaired during the progression of heart failure. Although the mechanism of induction of apoptosis in the failing heart varies according to the model of heart failure, it is not known whether an impairment of energy metabolism in cardiomyocytes is a primary cause of apoptosis. In this study, we applied mitochondrial inhibitors, such as rotenone, cobalt chloride and antimycin A, which inhibit mitochondrial function at different sites of the mitochondrial respiratory chain, to cardiomyocytes. All these reagents markedly decreased 3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay (MTT) reduction activity, an indicator of mitochondrial function, of cardiomyocytes and greatly increased glucose consumption, suggesting that cardiac energy metabolism is switched from beta-oxidation of fatty acid to glycolysis. It was shown that after 48-72 h of treatment with each reagent, apoptosis was shown to occur by DNA laddering and increase in caspase activity. Interestingly, each reagent with a different action site greatly activated caspase-3, but not caspase-8 activity, suggesting that mitochondria are involved in induction of apoptosis. On the other hand, within 24 h of the treatment, when apoptosis of cardiomyocytes was not observed, the treated cardiomyocytes showed a marked increase in preproendothelin-1 and atrial natriuretic peptide (ANP) gene expressions. In conclusion, the present study suggests that mitochondrial dysfunction with impaired energy metabolism elevates gene expression of cardiac ET-1, an aggravating factor in heart failure, and then finally induces apoptosis in cardiomyocytes. The finding of marked increases in expression of molecular markers (ET-1 mRNA and ANP mRNA) in the failing heart, followed by apoptosis in the treated cardiomyocytes suggests that the inhibition of mitochondrial function of cultured cardiomyocytes provides a possible new in vitro model of heart failure.
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PMID:Mitochondrial dysfunction of cardiomyocytes causing impairment of cellular energy metabolism induces apoptosis, and concomitant increase in cardiac endothelin-1 expression. 1107 77

Doxorubicin (DOX) is widely used to treat patients suffering from cancer, but the usage for patients is limited because of the dose-dependent cardiotoxicity. We hypothesized that DOX induces apoptosis through caspase activation in cardiomyocytes, and we examined this hypothesis using both rat primary cultured cardiomyocytes and rat hearts from an animal model. Cardiomyocytes were treated with DOX for 24 h. The activity of caspase-3 was significantly increased by DOX treatment. In rats with DOX injected intravenously once a week for 5 weeks, left ventricular fractional shortening evaluated by echocardiography was significantly decreased at age 14 weeks, 2 weeks after the end of DOX-administration. At 16 weeks of age, endothelin-1 mRNA and atrial natriuretic peptide mRNA were also significantly increased, likewise, and TUNEL positive cells were significantly increased in the ventricles of DOX-treated rats. The activity of caspase-3 in the ventricles was also significantly increased compared to that of untreated rats at 16 weeks. However, the activity of caspase-8 and the expression level of Fas-ligand mRNA were comparable with those of the untreated rats. In conclusion, DOX induces apoptosis through the activation of caspase-3, suggesting that apoptosis has an important role in the progression of cardiomyopathy due to DOX.
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PMID:Doxorubicin induces apoptosis by activation of caspase-3 in cultured cardiomyocytes in vitro and rat cardiac ventricles in vivo. 1676 56